1. Field of the Invention
The present invention relates to a pixel structure and an active device array substrate, and more particularly to a pixel structure and an active device array substrate capable of improving display quality.
2. Description of Related Art
Recently, the advancement of semiconductor devices and display devices flourishingly spreads the development of the multi-media technology. In respect of displays, thin-film transistor liquid-crystal displays (TFT-LCD) having superior features, such as high definition, compressed space occupation, low power consumption, and free of radiation gradually becomes the mainstream product in the market. A TFT-LCD is mainly constituted of a TFT array substrate, a color filter substrate, and a liquid crystal layer between two substrates.
FIG. 1A is a schematic view of a circuit of a conventional TFT array substrate. Referring to FIG. 1A, the conventional TFT-array substrate 100 includes a plurality of scan lines S1-Sn, a plurality of data lines D1-Dn, and a plurality of pixel structures P1-Pi. Specifically, the pixel structures P1-Pi are electrically connected to the corresponding scan lines S1-Sn and data lines D1-Dn. As shown in FIG. 1A, the pixel structure P1 is electrically connected to the scan line S1 and the data line D1. Actually, a switch signal transmitted by the scan line S1 may turn on the TFT T1. After the TFT T1 has been turned on, a display signal may be transmitted to the pixel structure P1 through the data line D1. It should be noted that the switch signal received by a farther TFT T1 may be decayed due to the influences of a resistance-capacitance delay (RC delay), a capacitance coupling effect, or a load.
FIG. 1B is a schematic view of a pixel voltage decay of the pixel structure P1 in FIG. 1A, and FIG. 1C is a schematic view of a pixel voltage decay of a farther pixel structure Pi in FIG. 1A. Referring to FIGS. 1B and 1C, when the pixel structure P1 receives the switch signal G1, the switch signal G1 may keep the TFT T1 turning on for a period of time, so as to allow the display signal da1 to be transmitted to the pixel structure P1. When the TFT T1 is turned off, the display signal da1 can not be continuously transmitted to the pixel structure P1, and thus the pixel voltage dr1 has a voltage drop. The voltage drop is called a feedthrough voltage ΔVp1.
It should be noted that the switch signal G1′ received by the remote TFT Ti is decayed due to the influences of the circuit delay, the capacitance coupling effect, or the load. Especially, in a large-sized liquid crystal display panel, the feedthrough voltage ΔVp2 of the remote pixel structure Pi is smaller than the feedthrough voltage ΔVp1 of the pixel structure P1. In this manner, the difference between the feedthrough voltages ΔVp1 and ΔVp2 may possibly cause an effect of flicker in display frame, which degrades display quality. Therefore, it is necessary to make improvement.